c# - 关闭没有 Flush() 的文件流

Question

我可以在不调用 Flush 的情况下关闭文件流吗？ (在 C# 中)？我明白 Close和 Dispose首先调用 Flush 方法。

Answer 1

MSDN 不是 100% 清楚，但 Jon Skeet 说“冲洗”，所以在关闭/处置之前进行。不会痛的，对吧？

来自 FileStream.Close Method :

Any data previously written to the buffer is copied to the file before the file stream is closed, so it is not necessary to call Flush before invoking Close. Following a call to Close, any operations on the file stream might raise exceptions. After Close has been called once, it does nothing if called again.

Dispose 不是很清楚:

This method disposes the stream, by writing any changes to the backing store and closing the stream to release resources.

备注:评论员可能是对的，从同花顺中不能100%清楚:

Override Flush on streams that implement a buffer. Use this method to move any information from an underlying buffer to its destination, clear the buffer, or both. Depending upon the state of the object, you might have to modify the current position within the stream (for example, if the underlying stream supports seeking). For additional information see CanSeek.

When using the StreamWriter or BinaryWriter class, do not flush the base Stream object. Instead, use the class's Flush or Close method, which makes sure that the data is flushed to the underlying stream first and then written to the file.

测试:

var textBytes = Encoding.ASCII.GetBytes("Test123");
using (var fileTest = System.IO.File.Open(@"c:\temp\fileNoCloseNoFlush.txt", FileMode.CreateNew))
{
    fileTest.Write(textBytes,0,textBytes.Length);
}
using (var fileTest = System.IO.File.Open(@"c:\temp\fileCloseNoFlush.txt", FileMode.CreateNew))
{
    fileTest.Write(textBytes, 0, textBytes.Length);
    fileTest.Close();
}
using (var fileTest = System.IO.File.Open(@"c:\temp\fileFlushNoClose.txt", FileMode.CreateNew))
{
    fileTest.Write(textBytes, 0, textBytes.Length);
    fileTest.Flush();
}
using (var fileTest = System.IO.File.Open(@"c:\temp\fileCloseAndFlush.txt", FileMode.CreateNew))
{
    fileTest.Write(textBytes, 0, textBytes.Length);
    fileTest.Flush();
    fileTest.Close();
}

我能说什么......所有文件都有文本 - 也许这只是数据太少？

测试2

var rnd = new Random();
var size = 1024*1024*10;
var randomBytes = new byte[size];
rnd.NextBytes(randomBytes);
using (var fileTest = System.IO.File.Open(@"c:\temp\fileNoCloseNoFlush.bin", FileMode.CreateNew))
{
    fileTest.Write(randomBytes, 0, randomBytes.Length);
}
using (var fileTest = System.IO.File.Open(@"c:\temp\fileCloseNoFlush.bin", FileMode.CreateNew))
{
    fileTest.Write(randomBytes, 0, randomBytes.Length);
    fileTest.Close();
}
using (var fileTest = System.IO.File.Open(@"c:\temp\fileFlushNoClose.bin", FileMode.CreateNew))
{
    fileTest.Write(randomBytes, 0, randomBytes.Length);
    fileTest.Flush();
}
using (var fileTest = System.IO.File.Open(@"c:\temp\fileCloseAndFlush.bin", FileMode.CreateNew))
{
    fileTest.Write(randomBytes, 0, randomBytes.Length);
    fileTest.Flush();
    fileTest.Close();
}

再一次 - 每个文件都有它的字节......对我来说，它看起来就像我从 MSDN 上读到的那样:在处理之前调用 Flush 或 Close 并不重要......对此有什么想法吗？